1,2

If gcd(m,n) = 1 then a(m*n) = (a(m) * a(n)) mod 9. - Robert Israel, Sep 14 2014

Robert Israel, Table of n, a(n) for n = 1..10000

a(n) = A010878(A000203(n)). - Michel Marcus, Sep 14 2014

seq(numtheory:-sigma(n) mod 9, n=1..1000); # Robert Israel, Sep 14 2014

(PARI) a(n)=sigma(n)%9

Cf. A190998 (digital root of sigma(n)).

Sequence in context: A323394 A017665 A248789 * A190998 A067342 A322656

Adjacent sequences: A105849 A105850 A105851 * A105853 A105854 A105855

easy,nonn

Shyam Sunder Gupta, May 05 2005

Name corrected and keyword base removed by Michel Marcus, Sep 14 2014

approved